Department of Geography, Université Catholique de Louvain, Place Pasteur 3, 1348, Louvain-la-Neuve, Belgium.
Ecohealth. 2009 Mar;6(1):135-47. doi: 10.1007/s10393-009-0236-y. Epub 2009 May 16.
The Camargue, a region in southern France, is considered a potential site for malaria reemergence. All the suitable factors of the disease transmission system are present -- competent mosquito vectors, habitats for their breeding, and susceptible people -- except for the parasite. The objective of this study was to test potential drivers of malaria reemergence in this system after possible changes in biological attributes of vectors, agricultural practices, land use, tourism activities, and climate. Scenarios of plausible futures were formulated and then simulated using a spatially explicit and dynamic multiagent simulation: the MALCAM model. Scenarios were developed by varying the value of model inputs. Model outputs were compared based on the contact rate between people and potential malaria vectors, and the number of new infections in case of reintroduction of the parasite in the region. Model simulations showed that the risk of malaria reemergence is low in the Camargue. If the disease would reemerge, it would be the result of a combination of unfavorable conditions: introduction of a large population of infectious people or mosquitoes, combined with high levels of people-vector contacts resulting from significant changes in land use, tourism activities, agricultural policies, biological evolution of mosquitoes, and climate changes. The representation in the MALCAM model of interactions and feedbacks between different agents, and between agents and their environment, led in some cases to counterintuitive results. Results from scenario analyses can help local public health authorities in policy formulation.
法国南部的卡马格地区被认为是疟疾再现的潜在地点。除了寄生虫之外，疾病传播系统的所有适宜因素——有能力的蚊子媒介、繁殖栖息地和易感人群——都存在。本研究的目的是在媒介生物的生物学特性、农业实践、土地利用、旅游活动和气候可能发生变化后，测试该系统中疟疾再现的潜在驱动因素。通过改变模型输入值来制定合理的未来情景，并使用空间明确和动态的多主体模拟：MALCAM 模型进行模拟。根据人与潜在疟疾媒介之间的接触率以及寄生虫在该地区重新引入后的新感染数量，对模型输出进行比较。模型模拟表明，卡马格地区疟疾再现的风险较低。如果疾病再次出现，这将是不利条件的综合结果：引入大量具有传染性的人群或蚊子，加上土地利用、旅游活动、农业政策、蚊子生物进化和气候变化导致的人与媒介接触水平的显著提高。MALCAM 模型中不同主体之间以及主体与其环境之间的相互作用和反馈的表示，在某些情况下导致了违反直觉的结果。情景分析的结果可以帮助地方公共卫生当局制定政策。
